EP0084797B1 - Procédé pour la fabrication d'un milieu de mémoire magnétique avec des liants durcissables par rayonnement - Google Patents

Procédé pour la fabrication d'un milieu de mémoire magnétique avec des liants durcissables par rayonnement Download PDF

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Publication number
EP0084797B1
EP0084797B1 EP83100179A EP83100179A EP0084797B1 EP 0084797 B1 EP0084797 B1 EP 0084797B1 EP 83100179 A EP83100179 A EP 83100179A EP 83100179 A EP83100179 A EP 83100179A EP 0084797 B1 EP0084797 B1 EP 0084797B1
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Prior art keywords
meth
acrylate
production
magnetic storage
storage medium
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EP83100179A
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German (de)
English (en)
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EP0084797A2 (fr
EP0084797A3 (en
Inventor
Herman Dr. Brinkmeyer
Hermann Dr. Perrey
Gerhard Dr. Hübler
Burkhard Dr. Nippe
Heinrich Dr. Kober
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Emtec Magnetics GmbH
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Agfa Gevaert AG
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    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/68—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
    • G11B5/70—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer
    • G11B5/702—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the bonding agent
    • G11B5/7026—Radiation curable polymers
    • G—PHYSICS
    • G11—INFORMATION STORAGE
    • G11B—INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER
    • G11B5/00—Recording by magnetisation or demagnetisation of a record carrier; Reproducing by magnetic means; Record carriers therefor
    • G11B5/62—Record carriers characterised by the selection of the material
    • G11B5/68—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent
    • G11B5/70—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer
    • G11B5/702—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the bonding agent
    • G11B5/7023—Record carriers characterised by the selection of the material comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent on a base layer characterised by the bonding agent containing polyesters, polyethers, silicones, polyvinyl resins, polyacrylresins or epoxy resins

Definitions

  • the present invention relates to a method for producing a magnetic recording medium with a magnetic layer, produced from olefinically unsaturated, radiation-curing binders and magnetic pigment.
  • Magnetic recording media such.
  • B. Magnetic tapes consist of a carrier film on which a dispersion of magnetic pigment is applied in a binder.
  • thermoplastic resins such as various copolymers, urethane elastomers, polyesters or polyamides
  • high-quality magnetic tapes are also used as binders which can be crosslinked with polyfunctional icoxyanates.
  • examples include higher molecular weight polyhydroxyl compounds, such as partially saponified vinyl chloride-vinyl ester copolymers, copolymers of vinyl chloride with hydroxyl-containing olefinically unsaturated monomers such as allyl alcohol and hydroxyalkyl (meth) acrylates, hydroxyl-containing polyester and polyurethane resins.
  • Such systems are described, for example, in German Auslegeschrift 11 06959 and 12 82 700.
  • binders for magnetic recording media which have an improved pot life. This is achieved in that the usual excess of isocyanate required for crosslinking can be reduced by using radiation-curing binders consisting of a mixture of a polyisocyanate and an active hydrogen-containing monomer, oligomer or polymer and / or an active hydrogen and also at least one unsaturated bond per molecule containing monomers, oligomers or polymers.
  • This binder mixture can be used to produce a dispersion containing magnetic pigment, which, as stated in the examples of DE-OS 30 29 818, is dried, calendered and subjected to a 24-hour heat curing at 60 ° C. after application, for example, on a carrier film. Electron beam curing is then carried out to ensure sufficient crosslinking.
  • a radiation-hardened magnetic recording medium which is obtained with a binder formulation consisting of a.
  • a magnetic dispersion can be produced from such a binder formulation and a magnetic pigment and further additives using a solvent or solvent mixture.
  • Low molecular weight, volatile acrylic compounds in the binder formulation have the disadvantage, however, that they accumulate in the recovered solvents when the applied magnetic dispersion dries, and thus do not allow the solvents to be reused without appropriate workup.
  • these losses of acrylic compounds in the binder formulation result in a non-uniform crosslinking density when crosslinking with electron beams.
  • the radiation essentially only leads to self-crosslinking of the acrylate portion.
  • German Auslegeschrift 21 00 037 magnetic recording media which by irradiation by means of ionizing rays of a magnetic dispersion consisting of a radiation-curing acrylic and / or methacrylic group-containing binder formulation with a viscose between 0.05 and 3 Pa - s (20 ° C) and a magnetic pigment.
  • a calendering as is required in the production of magnetic tapes, leads to considerable problems with the binder formulations described in this patent and is generally only possible after technically complex pre-crosslinking.
  • WO 81/02646 discloses magnetic recording media which are produced using a combination of radiation-curable binders A, B and, if appropriate, C.
  • the binder 1 has a molecular weight greater than 5,000
  • the binder B has a molecular weight between 400 and 5,000
  • the binder C has a molecular weight below 400.
  • a combination of the binders A and C is not preferred for the reasons described above .
  • reaction-improving, radiation-curing oligomers B are also used here.
  • Clear coat films of such radiation-cured binder, however ormul réelleen f show that the films have only an inadequate elasticity. This is particularly disadvantageous since, as is known, the high pigment content used in magnetic recording media also drastically reduces the elasticity of the coatings.
  • dispersion such binder formulations also do not meet the requirement for a narrow molecular weight distribution of the binders.
  • olefinically unsaturated, radiation-curable binder which contains a polyurethane with an average molecular weight and end-chain and chain-side acryloyl and / or methacryloyl groups via urethane, allophane and / or urea bridges M w is from 10,000 to 200,000 (weight average), or that the above-mentioned binder B is used in combination with a binder A known per se, which is a polymer containing acryloyl and / or methacryloyl groups, and by reacting an active hydrogen-containing polymer with an average molecular weight M w of 10,000 to 200,000 (weight average) and a polyfunctional isocyanate and a hydroxyalkyl acrylate and / or oligoacrylate and / or oligomethacrylate, and that the binder and magnetic pigment containing dispersion by electrons radiation is hardened.
  • the binders A on which the invention is based are polymers containing acryloyl and / or methacryloyl groups which result from an active hydrogen-containing polymer such as, for. B. alkyd resins, polyesters, unsaturated polyesters, polyethers, polyepoxides, polyacrylates, phenolic resins, polyamides, melamine resins, urea resins, silicone resins, celluloses, but in particular, however, partially saponified vinyl chloride-vinyl ester copolymers and copolymers of vinyl chloride and allyl alcohol and / or hydroxyalkyl (meth) acrylates .
  • an active hydrogen-containing polymer such as, for. B. alkyd resins, polyesters, unsaturated polyesters, polyethers, polyepoxides, polyacrylates, phenolic resins, polyamides, melamine resins, urea resins, silicone resins, celluloses, but in particular, however, partially saponified vinyl chloride
  • Carriers for the active hydrogen in these polymers are carboxyl, primary and secondary amino, mercapto and hydroxyl groups.
  • the polyfunctional isocyanates can be any organic isocyanate compounds that have at least two free isocyanate groups. Di- and trifunctional isocyanate compounds and mixtures thereof are preferably used.
  • Examples include: tolylene diisocyanate, diphenylmethane diisocyanate, isophorone diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, triphenylmethane triisocyanate, the products obtained by reaction of trimethylolpropane and diisocyanates in a ratio of 1: 3 and the triisocyanates obtained by reacting diisocyanates with water.
  • Such combinations are, for example, 1 mole of 2,4-tolylene diisocyanate and 1 mole of trimethylol propane diacrylate or 1 mole of triphenylmethane triisocyanate and 2 moles of hydroxyethyl acrylate; each combination based on 1 mol of active hydrogen of a polymer.
  • the reaction can be carried out by introducing the active hydrogen-containing polymer and hydroxyalkyl (meth) acrylate or an oligoacrylate containing one hydroxyl group per molecule be and the isocyanate is added.
  • a two-stage process is preferred, in the first stage of which the polyfunctional isocyanate is reacted with a hydroxyalkyl (meth) acrylate and / or an oligo (meth) acrylate containing one hydroxyl group per molecule, preferably in a ratio such that only one isocyanate group per Molecule remains.
  • the reaction with the active hydrogen-containing polymer takes place.
  • these reactions, in particular the second stage are carried out in the presence of a solvent or solvent mixture which is not capable of reacting with free isocyanate, such as. B.
  • reaction temperatures in these reactions are generally 20-90 ° C, but higher temperatures can also be used under certain circumstances.
  • the reaction of the polyisocyanates with the active hydrogen-containing polymers and one hydroxyl group per molecule-containing hydroxyalkyl (meth) acrylates and / or oligo (meth) acrylates can be carried out in a manner known per se, e.g. B. with tin octoate, dibutyltin dilaurate or tert. Amines are catalyzed.
  • binder A is used only in combination with binder B or exclusively binder B, which is a polyurethane and carries (meth) acryloyl groups on the chain end and chain side via urethane, allophane and / or urea bridges.
  • the chain frame is a polyurethane.
  • Such polyurethanes are obtained by reacting an aliphatic and / or aromatic diisocyanate with a chain-extending dihydroxy compound.
  • aliphatic and aromatic diisocyanates are: butylene-1,4-diisocyanate, hexamethylene diisocyanate, polymethylene diisocyanate, 2,4-toiuyien diisocyanate, 2,6-tolylene diisocyanate. anate, diphenylmethane-4,4-diisocyanate and the isomers and isomer mixtures, p-phenylene diisocyanate, m-phenylene diisocyanate and 2,4-naphthalene diisocyanate.
  • chain-extending dihydroxy compounds are: ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,4-butanediol, 1,6-hexanediol, 1,4-bis (hydroxymethyl) cyclohexane , 1,4-dihydroxycyclohexane, diethylene glycol, triethylene glycol, octaethylene glycol, bis (2-hydroxyethyl) methylamine and also linear, hydroxyl-terminated polyesters from, for example, the aforementioned dihydroxy compounds and one of the known aliphatic, cycloaliphatic or aromatic dicarboxylic acids such as, for. B.
  • succinic acid glutaric acid, adipic acid, suberic acid, 1,4-cyclohexanedicarboxylic acid, hexahydrophthalic acid, phthalic acid, terephthalic acid, fumaric acid, maleic acid and the like.
  • the polyurethanes can also have smaller proportions of urea segments which are obtained by using compounds such as 2-methylaminoethanol, N, N'-dimethylethylenediamine and primary amines such as butylamine or hexylamine.
  • Trifunctional compounds such as glycerol, trimethylolpropane, 2-aminoethanol, bis (2-hydroxyethyl) amine and the like can also be used to a small extent with respect to an isocyanate reaction.
  • Compounds such as, for example, glycerol and 2-aminoethanol, the active hydrogen atoms of different reactivity towards isocyanates, are preferred.
  • the molecular weight of the polyurethanes formed can be regulated in a polyaddition reaction, and hydroxyl-terminated polyurethanes are also obtained.
  • These terminal hydroxyl groups, the active hydrogen atoms of the urethane bonds and those caused by the trifunctional compounds can be reacted with polyfunctional isocyanates and one hydroxyalkyl (meth) acrylate and / or oligo (meth) acrylate per molecule, as described below the section on binder A has been carried out.
  • Also preferred here is a two-stage process, in the first stage of which the polyfunctional isocyanate is reacted with a hydroxyalkyl (meth) acrylate and / or an oligo (meth) acrylate containing one hydroxyl group per molecule, preferably in a ratio such that only one isocyanate group remains per molecule.
  • a second stage the reaction with the active hydrogen-containing polyurethanes takes place.
  • these reactions, in particular the second stage are carried out in the presence of a solvent or solvent mixture which is not capable of reacting with free isocyanate, such as. B.
  • reaction temperatures in these reactions are generally 20-90 ° C, but higher temperatures can also be used under certain circumstances.
  • the reaction of the polyisocyanates with the active hydrogen-containing polyurethanes and one hydroxy group per molecule containing hydroxyalkyl (meth) acrylates and / or oligo (meth) acrylates can be carried out in a manner known per se, e.g. B. with tin octoate, dibutyltin dilaurate or tert. Amines are catalyzed.
  • Another advantageous method of producing (meth) acryloyl group-containing polyurethanes of the binder B type is to react difunctional urethane (methane) acrylates as chain extenders with difunctional isocyanates with regard to active hydrogen atoms.
  • Such difunctional urethane (meth) acrylates containing active hydrogen atoms are obtained by reacting an at least difunctional isocyanate with a hydroxyalkyl (meth) acrylate and / or oligo (meth) acrylate containing one hydroxyl group per molecule and a compound which is trifunctional in terms of active hydrogen atoms.
  • Suitable polyisocyanates and one hydroxy group have been described previously.
  • Examples of compounds which carry trifunctional active hydrogen atoms are glycerol, trimethylolpropane, pentaerythritol, bis- (2-hydroxyethyl) amine and 2-aminoethanol.
  • the reaction is preferably carried out in such a way that in a first stage an at least difunctional isocyanate is reacted with a hydroxyalkyl (meth) acrylate and / or oligo (meth) acrylate containing one hydroxyl group per molecule in a molar ratio such that one mole of isocyanate remains per mole of reaction product .
  • the remaining isocyanate is reacted with one of the trifunctional compounds already exemplified in a molar ratio of 1: 1.
  • the reaction temperatures are generally between 20 and 90 ° C.
  • the reactions can be accelerated by the known catalysts. To regulate the viscosity, the reactions can be carried out in the inert solvents already mentioned.
  • urethane (meth) acrylates which act as chain extenders, can be reacted alone or in combination with the dihydroxy compounds already mentioned above and the difunctional isocyanates in a polyaddition reaction.
  • compounds such as 2-methylaminoethanol, N, N-dimethylethylenediamine, primary amines such as butylamine and hexylamine and also branching compounds such as glycerol, trimethylolpropane, 2-aminoethanol, bis- (2-hydroxyethyl) amine can also be used to a small extent .
  • the molecular weight of these polyurethanes can be regulated by an excess of the chain-extending compounds or by adding a monofunctional compound such as. B. methanol, ethanol, cyclohexanol, butylamine.
  • the polyaddition reaction can also be accelerated by the catalysts already described as examples.
  • reaction temperatures are 20 ° to 90 ° C, but higher temperatures can be used if necessary, provided that the inert solvents or solvent mixtures used as the reaction medium permit this.
  • Suitable solvents are e.g. B. tetrahydrofuran, dioxane, acetone, butanone, cyclohexanone, methyl isobutyl ketone, cyclohexane, toluene, methylene chloride, ethylene glycol dimethyl ether, ethyl acetate, butyl acetate, dimethylformamide, dimethyl sulfoxide.
  • Another method of producing a B-type polyurethane is that a difunctional isocyanate is used in the polyaddition reaction described above, which is obtained by reacting an at least trifunctional isocyanate with a hydroxyalkyl (meth) acrylate and / or oligo containing one hydroxyl group per molecule (Meth) acrylate is obtained, the molar ratio of isocyanate to hydroxyl compound being chosen so that two isocyanate groups are retained per molecule.
  • such compounds can be obtained by reacting 1 mole of triphenylmethane triisocyanate with 1 mole of 2-hydroxyethyl acrylate.
  • inhibitors and antioxidants added in the production of the (meth) acryloyl-containing binders A and B which are added in amounts of 0.001-0.1% by weight, based on the mixture as a whole, do not guarantee adequate dark storage stability, these inhibitors and Antioxidants can be post-stabilized.
  • auxiliaries of this type are, for example, phenols and phenol derivatives, preferably sterically hindered phenols, which contain alkyl substituents with 1-6 C atoms in both o-positions to the phenolic hydroxyl group, amines, preferably secondary acrylamines and their derivatives, quinones, copper-I salts organic acids or addition compounds of copper (1) halides on phosphites.
  • (meth) acryloyl-containing binders A in combination with (meth) acryloyl-containing binders B or only (meth) Acryloyl-containing binders B are ground and ground with a magnetic pigment using a solvent or solvent mixture by known processes.
  • All substances suitable for storage purposes such as ⁇ -Fe 2 O 3 , mixed crystals of -y-Fe 2 O 3 and Fe 3 O 4 , cobalt-doped ⁇ -Fe 2 O 3 or Fe 3 O 4 , CrO are suitable as magnetic pigment 2 , barium ferrite, ferrimagnetic alloys such as Fe-Co, Co-Ni, Fe-Co-Ni, Fe-Co-B, Fe-Co-Cr-B, Mn-Bi, Mn-AI, Fe-Co-V, iron nitride or mixtures of these substances.
  • protic solvents can also be used in addition to the aprotic solvents or solvent mixtures already mentioned, such as, for. As ethanol, isopropanol, butanol and. a.
  • dispersion aids will be used for the production of the magnetic dispersion, which in any case must be matched to the pigment, the solvent and the other formulation components as well as the properties of the finished layer.
  • the selection is made from the large number of known surface-active compounds, such as. B. lecithin, cephalin, fatty acid amides or diamides or their ammonium salts, ethoxylated fatty acid derivatives, aliphatic or aromatic optionally ethoxylated phosphoric acid esters, sulfosuccinic acid esters, sorbitan esters, aliphatic or aromatic sulfonic acids or sulfonates, fatty alcohol sulfates and others.
  • lubricants such as. B. fatty acids or fatty acid derivatives, silicone oils, paraffins, waxes, fluorinated oils, dispersions of polytetrafluoroethylene.
  • Other possible additives include plasticizers, abrasives, viscosity regulators and the like.
  • the coating dispersion is produced in a known manner by mixing the magnetic material with a suitable solvent using a kneader, stirrer, dissolver, or by means of other mixing units.
  • the solvent can contain the dissolved binder in whole or in part, as well as dispersants or other additives.
  • the premixed dispersion is usually subjected to a milling process until the magnetic pigment is sufficiently distributed.
  • the grinding takes place e.g. B. in ball mills, pearl mills, sand mills or similar. residual binder or additives are mixed in after the grinding process.
  • the magnetic dispersion is applied by applying a magnetic field using a suitable unit (reverse roll coater, raster printer, extrusion molding machine) to a non-magnetizable carrier, which is made, for example, of a polyester such as polyethylene terephthalate, a polyolefin such as polypropylene, a cellulose ester such as cellulose diacetate or cellulose triacetate , a polycarbonate, polyamide, polyimide, paper, a metal foil, aluminum or copper or other material.
  • a suitable unit reverse roll coater, raster printer, extrusion molding machine
  • the uncured magnetic recording layer can be subjected to calendering and then cured with ionizing rays (electron, neutron, gamma, X-rays). Curing is preferably carried out by electron beams with a radiation dose of 0.5-25 Mrad, in particular of 0.5-10 Mrad. In order to achieve sufficient deep hardening, the accelerator voltage should not be below 100 kV.
  • a higher accelerator voltage enables, particularly in the case of strip material, the simultaneous and very economical curing of several strip layers under one radiation source, so that high production speeds can be achieved.
  • hydroxyethyl acrylate are slowly added dropwise to 286 g of polyfunctional aliphatic polyisocyanate (Desmodur N R , manufactured by Bayer AG) and 0.16 g of phenothiazine while passing air through at 60 ° C. After the addition is complete, the temperature is kept at 60 ° C. until the isocyanate content has dropped to 6%. Then 1,644 g of butanone, 2.2 g of tin (11) octoate and 460 g of partially hydrolyzed copolymer of vinyl chloride and vinyl acetate (VAGH, manufactured by UCC Co. Ltd.) with an average molecular weight M w of 105,000 (determined by light scattering measurements) stirred in. The reaction is carried out at 60 ° C. until isocyanate can no longer be detected. The fixed salary is determined at 35%.
  • Polyfunctional aliphatic polyisocyanate (Desmodur N R , manufactured by Bayer AG) and 0.16 g of phen
  • Diol and polyols as chain extenders with an aromatic polyisocyanate (Impranil CHW R , manufactured by Bayer AG), dissolved in 1414.8 g of butanone, and 530 g of butanone were added. The reaction is carried out at 65 ° C. until isocyanate can no longer be detected. The fixed salary is determined at 30%.
  • a magnetic coating dispersion is produced from the following components
  • the mixture is predispersed in a disperser and ground in a stirred ball mill for 3 hours.
  • the coating varnish is poured onto a 15 ⁇ m polyester film (dry layer thickness 5 ⁇ m) and, after drying, calendered with a line pressure of 80 kg / cm.
  • the coated material is then irradiated in an electron beam system with a dose of 10 Mrad at an acceleration voltage of 175 kV and then separated.
  • a magnetic coating dispersion is produced by mixing the following components:
  • a magnetic coating dispersion is produced by mixing the following components: Processing is carried out analogously to Example 8.
  • the magnetic coating dispersion is made from the mixture of the following components:
  • a magnetic lacquer is produced by mixing the following components:
  • the magnetic dispersions produced with the aid of the olefinically unsaturated, radiation-curing binders described are distinguished by a practically unlimited pot life.
  • the magnetic materials formed by pouring these magnetic dispersions onto suitable substrates have the preferred property that they can be calendered without pre-crosslinking.
  • the magnetic layers produced according to the invention are completely crosslinked immediately after the irradiation. They are characterized by the lowest tendency to stick, improved mechanical compared to conventional systems and storage technology values, excellent solvent resistance and crosslinking.
  • the degree of crosslinking achieved is determined quantitatively using the swelling temperature method (K. Ch. Scangefarth, Aid + Lack 84, 13 (1978)). The method is based on the effect that the magnetic layers applied to non-magnetic substrates suddenly unfold after a period of time after immersion in suitable thermostated solvents.
  • the magnetic tape sample to be examined (1 cm x 2 cm) is immersed in a thermostatted bath with cyclohexanone. At constant bath temperatures between -15 ° C and 140 ° C, the time that elapses between the immersion of the sample and the sudden unfolding of the magnetic layer is determined. The bath temperature at which the layer unfolds exactly after 10 seconds is defined as the source temperature. It is a good quantitative measure of the degree of crosslinking of the layer. The results are shown in Table 1 below.
  • a clear lacquer film is produced from an oligoacrylate ( R Aronix M-8030 from Toa Gosei Kagaku Co.) and a thermoplastic polyurethane ( R Estane 5702 from Goodrich Co.) according to DE-OS 30 29 819.
  • a clear lacquer film according to WO 81/02646 is produced from the urethane acrylates a and g in a ratio according to example 1 of the patent application mentioned. The results are shown in Table 2.

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  • Paints Or Removers (AREA)

Claims (13)

1. Procédé de production d'un milieu magnétique d'enregistrement, principalement constitué d'un support de couche et d'une couche contenant des pigments magnétiques, qui contient des liants qui proviennent de polymères radiodurcissables à non-saturation, α,β-oléfinique, caractérisé en ce qu'on utilise un liant B qui est un polyuréthanne de poids moléculaire moyen Mp allant de 10000 à 200000 (moyenne en poids), portant des groupes acryloyle et/ou méthacryloyle en bout de chaîne et en chaîne latérale par l'intermédiaire de ponts uréthanne, allophane et/ou urée, ou en ce que le liant B mentionné ci- dessus est utilisé en association avec un liant A connu qui est un polymère porteur de groupes acryloyle et/ou méthacryloyle et qui est produit par réaction d'un polymère porteur d'hydrogène actif ayant un poids moléculaire moyen Mp de 10 000 à 200 000 (moyenne en poids) avec un isocyanate polyfonctionnel et un acrylate d'hydroxyalkyle et/ou un méthacrylate d'hydroxyalkyle et/ou un oligoacrylate et/ou un oligométhacrylate, et en ce que la dispersion contenant les liants et le pigment magnétique est durcie par un flux d'électrons.
2. Procédé de production d'un milieu magnétique d'enregistrement suivant la revendication 1, caractérisé en ce què le polymère contenant de l'hydrogène actif est au moins une résine alkyd, un polyester saturé, un polyester insaturé, un polyéther, un polyépoxyde, un polyacrylate, une résine phénolique, une résine polyaminée, une résine mélamine-aldéhyde, une résine urée-aldéhyde, une résine de silicone, une cellulose, un dérivé de cellulose, un copolymère de chlorure de vinyle et d'ester de vinyle partiellement saponifié ou un copolymère de chlorure de vinyle et d'alcool allylique ou de (méth) acrylate d'hydroxyalkyle.
3. Procédé de production d'un milieu magnétique d'enregistrement suivant la revendication 1, caractérisé en ce que les isocyanates polyfonctionnels sont constitués d'au moins un diisocyanatoto- luène, diisocyanatodiphénylméthane, isophoronediisocyanate, diisocyanatoxylène, hexaméthylènediiso- cyanate, triisocyanatotriphénylméthane, du produit de réaction du triméthylolpropane et d'un diisocyanate dans le rapport de 1 : 3 ou d'un triisocyanate qui est obtenu par réaction de diisocyanates avec l'eau.
4. Procédé de production d'un milieu magnétique d'enregistrement suivant la revendication 1, caractérisé en ce que les (méth) acrylates d'hydroxyalkyle et/ou les oligo(méth) acrylates sont constitués d'au moins un (méth) acrylate de 2-hiydroxyéthyle, 2-hydroxypropyle, 2-hydroxybutyle, 3-hydroxypropyle, 4-hydroxubutyle, 3-chloro-2-hydroxypropyle, 6-hydroxyhexyle, (méth) acrylate de glycérol, de triméthylolpropane, tri(méth) acrylate de pentaérythritol ainsi que des (méth) acrylates oxéthylés ou oxypropylés correspondants.
5. Procédé de production d'un milieu magnétique d'enregistrement suivant les revendications 1 à 4. caractérisé en ce que les polymères porteurs de groupes (méth) acryloyle utilisés comme liant A sont des produits réactionnels obtenus par une première réaction d'un isocyanate polyfonctionnel avec un (méth)-acrylate d'hydroxyalkyle et/ou un oligo(méth) acrylate dans un rapport choisi de manière qu'il reste simplement un groupe isocyanato par molécule, puis réaction avec un polymère contenant de l'hydrogène actif.
6. Procédé de production d'un milieu magnétique d'enregistrement suivant les revendications 1 à 5. caractérisé en ce qu'on utilise des associations de polyisocyanates, de (méth) acrylates d'hydroxyalkyle et/ou d'oligo(méth) acrylates qui conduisent à 2-3 groupes (méth) acryloyle par hydrogène actif du polymère ayant réagi.
7. Procédé de production d'un milieu magnétique d'enregistrement suivant la revendication 1. caractérisé en ce que le polyuréthanne porteur de groupes (méth) acryloyle est obtenu par réaction d'un polyuréthanne contenant de l'hydrogène actif avec un isocyanate polyfonctionnel et un (méth) acrylate d'hydroxyalkyle et/ou un oligo(méth) acrylate contenant un groupe hydroxyle par molécule.
8. Procédé de production d'un milieu magnétique d'enregistrement suivant les revendications 1 à 7. caractérisé en ce que les polyuréthannes contenant des groupes (méth) acryloyle utilisés comme liant B sont des produits réactionnels obtenus par une première réaction d'un isocyanate polyfonctionnel avec un (méth) acrylate d'hydroxyalkyle et/ou un oligo(méth) acrylate contenant un groupe hydroxyle par molécule dans un rapport choisi de manière qu'il reste un seul groupe isocyanato par molécule, puis réaction avec un polyuréthanne contenant de l'hydrogène actif.
9. Procédé de production d'un milieu magnétique d'enregistrement suivant la revendication 1, caractérisé en ce que les polyuréthannes porteurs de groupes (méth) acryloyle utilisés comme liants B sont obtenus par des réactions de polyaddition d'isocyanates difonctionnels et de (méth) acrylates d'uréthanne à effet d'allongement de chaîne, qui sont obtenus par réaction d'un isocyanate au moins -difonctionnel avec un (méth) acrylate .d'hydroxyalkyle et/ou un oligo(méth) acrylate portant un groupe hydroxyle par molécule, puis d'un composé trifonctionnel relativement aux atomes actifs d'hydrogène, et le cas échéant avec un composé difonctionnel vis-à-vis d'atomes actifs d'hydrogène, à effet d'allongement de chaîne, et le cas échéant de faibles quantités d'un composé trifonctionnel à effet ramificateur.
10. Procédé de production d'un milieu magnétique d'enregistrement suivant la revendication 1, caractérisé en ce que les polyuréthannes porteurs de groupes (méth) acryloyle utilisés comme liant B sont obtenus par des réactions de polyaddition avec utilisation d'isocyanates difonctionnels qui sont produits par réaction d'un isocyanate au moins trifonctionnel avec un (méth) acrylate d'hydroxyalkyle et/ou un oligo(méth) acrylate contenant un groupe hydroxyle par molécule, dans un rapport tel qu'il reste deux groupes isocyanato par molécule.
11. Procédé de production d'un milieu magnétique d'enregistrement suivant les revendications 1 à 10, caractérisé en ce que le pigment magnétique est formé d'oxyde de fer y, de magnétite, de phases mixtes de magnétite, d'oxydes de fer y, d'oxyde de fer dopé au cobalt, de ferrite, de dioxyde de chrome, d'un pigment métallique tel que le fer pur et/ou ses alliages.
12. Procédé de production d'un milieu magnétique d'enregistrement suivant les revendications 1 à 11, caractérisé en ce que les liants sont durcis par un flux d'électrons avec une dose d'irradiation de 0,5 à 10 Mrads.
13. Procédé de production d'un milieu magnétique d'enregistrement suivant la revendication 12, caractérisé en ce que les liants sont durcis avec une tension d'accélération d'au moins 100 kV.
EP83100179A 1982-01-14 1983-01-12 Procédé pour la fabrication d'un milieu de mémoire magnétique avec des liants durcissables par rayonnement Expired EP0084797B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3200970 1982-01-14
DE3200970A DE3200970C2 (de) 1982-01-14 1982-01-14 Magnetisches Speichermedium mit strahlenhärtbaren Bindemitteln

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EP0084797A2 EP0084797A2 (fr) 1983-08-03
EP0084797A3 EP0084797A3 (en) 1985-10-16
EP0084797B1 true EP0084797B1 (fr) 1987-12-23

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EP83100179A Expired EP0084797B1 (fr) 1982-01-14 1983-01-12 Procédé pour la fabrication d'un milieu de mémoire magnétique avec des liants durcissables par rayonnement

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EP (1) EP0084797B1 (fr)
DE (2) DE3200970C2 (fr)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4408020A (en) * 1982-06-28 1983-10-04 The B. F. Goodrich Company Curable polyurethanes
JPS6052922A (ja) * 1983-09-02 1985-03-26 Tdk Corp 磁気記録媒体
DE3513208A1 (de) * 1984-04-14 1985-10-17 Victor Company Of Japan, Ltd., Yokohama, Kanagawa Magnetisches aufzeichnungsmedium mit einem gehalt an einem speziellen copolymerenbindemittel
JPH0610856B2 (ja) * 1984-08-04 1994-02-09 ティーディーケイ株式会社 磁気記録媒体
US4842942A (en) * 1984-08-15 1989-06-27 Toyo Boseki Kabushiki Kaisha Magnetic recording medium
JPS62188019A (ja) * 1986-02-13 1987-08-17 Victor Co Of Japan Ltd 磁気記録媒体
JP2523279B2 (ja) * 1986-05-02 1996-08-07 ティーディーケイ株式会社 磁気記録媒体およびその製造方法

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2100037C3 (de) * 1971-01-02 1980-06-19 Hartmann, Job-Werner, Dr., 6700 Ludwigshafen Verfahren zur Herstellung von magnetischen Aufzeichnungsträgern
JPS5625230A (en) * 1979-08-06 1981-03-11 Sony Corp Magnetic recording medium
JPS56122802A (en) * 1980-03-03 1981-09-26 Toyo Ink Mfg Co Ltd Radiation-curable resin composition

Also Published As

Publication number Publication date
DE3200970A1 (de) 1983-07-28
DE3200970C2 (de) 1983-11-24
EP0084797A2 (fr) 1983-08-03
DE3375050D1 (en) 1988-02-04
EP0084797A3 (en) 1985-10-16

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